<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>画三角形</title>
    <style>
        body{
            background-color: #fff;
        }
        .content{
            width:0;
            height: 0;
            border-right: 100px black solid;  /*如果希望不显示这个三角形则设置成 transparent*/
            border-left: 100px blue solid;
            border-top: 100px yellow solid;
            border-bottom: 100px red solid;
        }
    </style>
</head>
<body>
    <div class="content">

    </div>
</body>
</html>